This invention relates to a level compression circuit which compresses the level of an audio signal. In particular, it relates to a level compression circuit in which a signal waveform is not significantly distorted when a signal is compressed.
Conventional portable home camcorders are known in which a magnetic tape is used to record video and sound signals. Such camcorders are equipped with a small built-in monitor such as a liquid crystal display. An image is played back on this monitor and sound is reproduced on a small speaker.
However, there is a problem with such prior art apparatus. There are occasions in which sound from the speaker becomes distorted. For example, let us assume that a conversation is recorded. Let us further assume and that the recorded sound level is low and that an operator is listening to the recorded audio at the maximum setting of the electronic volume control circuit. The recorded audio also includes a high-level engine noise of a passing car. Reproduced audio signals for the engine noise may exceed the dynamic range of the speaker amplifier. Then, the audio signals for the engine noise will be clipped and high frequency components will be generated. At this point, a problem arises in that a distortion is created and unpleasant audio noise exists. Limiter circuits have been used to reduce the distortion caused by over-driving small speakers; however, such limiters typically distort the waveform at large amplitude inputs, introducing distortion.